Water Striders

(Family Hydrobatidae.)
In this group belong most of the curious, slender, long­legged creatures known as water striders, which dart about on the surface of the water with such rapidity that it is very difficult to capture them. It is a large group and contains many different forms which are included in several subfamilies. They are found upon salt as well as upon fresh water.

They have prominent eyes, a stout beak, long antennae, and a usually tapering abdomen. Two different forms of the adult occur with most species, the one winged and the other wingless. The Oceanic forms are most abundant in the Sargasso Sea, resting upon and breeding among the great mass of accumulated seaweed. When storms break up this great island of vegetation portions of it are carried far and wide, and some of the Oceanic water bugs are therefore brought to our shores.

One of the commonest water striders of the United States is Hygrotrechus remigis Say. It is about a half-inch long, dark­brown in color, and moderately stout. It is everywhere seen skimming about on the surface of mill-ponds or similar bodies of water. It uses its slender, rather hairy hind legs as oars, practically rowing itself, and frequently congregates in groups with others of its kind in quiet places as though to talk over old times. Full-grown specimens are seen towards the end of summer, and at the approach of cold weather they hide away under the banks of streams in mud or beneath leaves, or at the bottom of the water under stones, and wait until spring. As the weather grows warmer they bob up to the surface of the water and prepare for egg-laying.

The eggs are whitish, translucent, and are long, nearly cylindrical, and blunter at one end than at the other. They are stuck on the leaves and stems of the water plants. The young strider does not issue from the egg by pushing off a cap at the end as do other water bugs, but by bursting through a slit which opens a little below the blunt end of the egg. The duration of the egg stage is about two weeks.

An extraordinary water-strider, known as Rheumatobates rileyi, was found near Washington, D.C., several years ago by Mr. Otto Heidemann, and has since been proved to be rather widely distributed. It is so extraordinary an insect in its general appearance that it has been adopted for the seal of the Entomological Society of Washington.

It is found on still waters, such as canals, and is carnivorous in its habits like the other members of the family. Although the water striders are truly aquatic, they are structurally more closely allied to the land bugs than to most of of the other water bugs, and especially in that they have free and conspicuous antennae, the water bugs of the group Cryptocerata having, as stated elsewhere, the antennae hidden in a pocket beneath the head.